SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '610d5bb583ca23ae8a4a6927344b9c79f213704e24b2133e46aaffc52fe55739' 
  AND token = 'C0/mjamvPy2ppctYv0uCIkh0b+5TtpzBmVfY6hdaKwY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}