SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c67bc277a4e17f600d53b2f24f9087820dc450fef236eff012e3f88e3544ca02' 
  AND token = 'B5QbDJMELv0H30aSGeGIa7XYYL21Eh7P/Qt9pYF5JCY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}