SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f6e5c457400a523e6a05c0dfa8b5a85342f7cf22bafacd82c74582ba73c4c9be' 
  AND token = 'CDVHiGihQbhQHoSFUafD92pnxXthL5rxPvMfpbTFLqI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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