SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b4f8f851696af5e68068518eaa1a34cb391dd0c83834e5539c51c1dc31cef434' 
  AND token = 'L5h5N2uPe0g37+PcqGO2FZCW7YH7NhuziDpNQKirnRQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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