SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '717afe139597db5fd32a2c2116d5b646b9873e9c3ac0bb223686a8a9bfd25fc5' 
  AND token = '4KLrCExhBe5Qzi7uDmAylt1XF/NNZaKYmKPSGLcuRfM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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