SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aa0b3504783ad1ebe03a2df47933e7cd11c2cca34b7c132b7f400befcdce8241' 
  AND token = 'gjeYi8q7yPRcqHTZYDkRONgCjBo3QNTWs/+cPtEEIg0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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