SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fff20e75ade6284d45cd0f6fa1bbbf75b320954f4243ac30bff4db7e8951bb8f' 
  AND token = 'vRBqcE9QA6Ind9yusBQ+HztRnFHp21Nmps3HnY/fsrY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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