SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f66dece1af95e833c5a721392ea33dab59a9f4bba7b241f6988eee0c9ae61c3e' 
  AND token = 'A0LU1cDyjBpHdGE0/nHejC3Cc5Xi5beNRcU+2erKEDs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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