SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3a4d0c988c5501a14765747f984006f488bbeb31d2fadcceae80e9cd44e3f166' 
  AND token = 'EgoX0tjMlcTnkqZOLeRT4lSr8y7Sm149LMw+L095RdI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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