SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '87b1bc8451d968a187bf45ac63b5554eb002d8108475de56fba06d836bb676ab' 
  AND token = 'SS9OhEOTDeX0rLejRhxRBN9S5AzdCqnZvWOsDOWdHk4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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