SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '261cfcde507424707ebae09f33de3ceb2c68312edb4ce5f9b7b074da56119b39' 
  AND token = 'PEzkxfPwHmOaTU9qYvUtjGaJn5ADU3wyOEf3ffFEb1M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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