SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5ac0c8816548097712cff95cf7bb28caa8edb1799d2ac953ee1c8ec382a28447' 
  AND token = 'rEGz0NVIdyIhoyTAyFzTBK+tkzZT2y1FGAe8PHDSEeM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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