SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '13dc998bc3fcad3ffca9c825da5f90f48a77530e8815e719309284eb6dcf7812' 
  AND token = 'dj6anh0MO/K1DqGjmBCbKKs+mZqoaehf3r4YH4iV/rE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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