SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6cfe7bbd50f388ccc02953186b96a1fa294a865d46e6bf2cca10dd91054962e0' 
  AND token = 'vFrym24BLi/0KeLdCFZ2df/r2n3gjMe7VZMmVCEqcxk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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