SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5688d958075a636a7476313984ea2c64d0b88e286fdb41a73d70424162abb03c' 
  AND token = 'rtJYG33gdzh3RMpPdAnz3Re5USpnOKrOaqToNvhzXg8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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