SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'af3990d491bf642f3b01b11f2f8417436a0f1400958495c1b4f7179dc4538c70' 
  AND token = 'f7wdlTmC8kMzjLtta2J2f5AGyz64ax1vxsfvn7Tw0hQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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