SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3578b1123476111699d64e1dece1ee7d4dbf82d96437a1abf0ace5531a2da924' 
  AND token = 'bDQiVGvTVCNVin3y87WAGgm/k9wGv8JNDNE1KSLhsKY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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