SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '29e00b8108628d04bffce358e8275f08547d8e5514c140ba608a88fa9f70790e' 
  AND token = 'BzFTEPBVBJVv+GGBz1idIvpBj9A9nTAL1LiRL03aZlY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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