SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ea321c17738f445d97f2ddfab618e7ac1aca532d28e3a6184190b1cbf384762f' 
  AND token = 'RNr920iBHWYhMbtCeW9dUvoBqIKsQmxlWSJrRXihLek=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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