SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4dc7d6989b090e662175cd785d08bb805b383ab1f8ca18b5586fec3351719706' 
  AND token = '6BBHbjJ9D7NTViyRurcF4ULmK7P8OhXuXkosVD61u1Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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