SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '943ee7a68160198fedeb5dac50200a81914dc02cbf66b358a867a0bd22a4a00e' 
  AND token = 'U4wXJF7eMtTfotJ5eV+Fp/QlfhR06SUIkAeATUcnftI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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