SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '975bc9c80dbd6a91c687294f7652c8b4edf5d4013e42ae56b1a21c069cae46a8' 
  AND token = 'jGXlLJsPyzCutMD6yVjg4ja3VqM0N5ZTLudYbHAzFOM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}