SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3a02e3a20bb738778a3f6ee88d62deffb92ca66df852a15ed188bffb2f933845' 
  AND token = '3T9+4mwf2IrQBnOV50TxLlUAWeTY0mIQYwBiwRm8vAg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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