SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'be998ff79a64a6e3d12bce47d170e6bb84de98b7697f83fd45c8e9130bd9f985' 
  AND token = 'jb0sEHBXOYxTm6yQLzKBStGLWXFlLdgwp2Ml6Iz4qWE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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