SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e9490a6672e7ae3ef1acb36460af60a13bdbe65b999225b189b52c7a83964fb8' 
  AND token = 'fHrbduth9T3mQZhpWZrizYacQbqx1vlu8uP5bEBrdo0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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