SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '11e75f654a084d945df72fe540c4dfa6266ee443a59cbeea4dbf0db41ccde4cf' 
  AND token = 'G4xCOntdd8hkCBX2hxspRk/Nn6jCiyIrz6T5EizU/ZI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}