SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '46ad8721e99853b247ac988a64c48235bcf83ef9fba070224583fd8148c6e103' 
  AND token = 'mVwTBZ0ObivQw9gRAfG7q3P2hM5U2S9gKaGuSrm7p48=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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