SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd397e1e2755a6fdfe599cbaa3caf8593f3e3b27dfe07e9e1472b6fd213cf8150' 
  AND token = 'F2Dwlfjat+zQ6fIN1Td6vciOKe4fBQjOMrjYjrWdyBQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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