SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'be8141052e7f30f6e8454e66897516d98fa7a39ae4c331a85b4899eb0b78b28b' 
  AND token = 'sZuDuUKbd+3e1gTB5aUJdwJQv3CsLfjSjkIJBgpgfYQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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