SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '77089d168f337861951c62d123878a6db7445ad41083e5798262d03ab5dc700a' 
  AND token = '+olITEHF0IiQ6HTi9FBGFZ83ikq/CYzXHUICdhkZLjQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00075

JSON explain

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