SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f465dd910079250bf269c485dd2d8347fff4b6da74284ca590373c31a0805444' 
  AND token = 'zjxgPxmna7uqn2RBVv75T4LIC/fiq+VLX1qbQnrkdxc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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