SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a45538aac098992ee2b850f29471ef6ebf3d23e3c2b1557191cabb947bacb518' 
  AND token = 'pTlM/ovDHI+97oruUNNhnXPPvr59M6P5woNPXRml0qU=' 
  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"
    }
  }
}