SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2c3d7f327e84989a5c479d060c3f23f14b794aa6d59cf0e80035cc3d9e191bc9' 
  AND token = 'NEpwPskFLjHR0MoLevuTzZH1vrsRpXWXU2hzyBLz6Cg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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