SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd3e8455f63761aa31bc24050b39069ff343e94f8226d5f8c0a9b2ec3d6bdd9b7' 
  AND token = 'O2D/JAf/O/62IDbQ14BDliZATgvT9zOmHECMou8Fw5o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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