SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0d139ccb9fe66b1213b54a46edce8d3816abded3585707bac95795a9f5215563' 
  AND token = 'tHweHIWLpahFZJWlxz0uCH6qhksSc58IYjmQFOjZVmc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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