SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '89039a637f0865c2b0f436caaddc5a25181ab46270cbc76cb362f6116323013b' 
  AND token = '8H0IgjvOPJm9mKWc6BQlASyqyIhLPkjpCKCbcHIdXw0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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