SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cc5c6cfb54b54979c7163222267b2095397881988ff621ffe039b338555b1db3' 
  AND token = 'sWCAR9lIXtEUHmANteZkAv/WHDoA77c/EpynUnrqqFA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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