SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5786861ba70eb1e8e736211575bcca42f7527e1e589780cab7ed4f03ffaa2cee' 
  AND token = 'BxNzVT4Hp4gZCy0Je+NgsaNbkeaxtxMDcLUEPTqPXdM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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