SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0b6fa0b4e692f715f383c240b30656ddc2207bf018729ca4ce862286b907587c' 
  AND token = 'CIQfKMBAd9pRIOaZvKciNynvlQQSdXaO18gaSQgvI2U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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