SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '371210446ff8d0362dacc3acab2d148b178ba171ce498675593aca87720c0829' 
  AND token = 'XN1MChNj62/tlQ8gCOnVTi2Gm0JPP2VxRGwIimWSOtA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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