SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b70e72e54a6ad370930438811696f973cb532853487b7c3cb1457b6a4a80b7e4' 
  AND token = 'uJQ5EJk+V/BhMm+p2HViok14PDDad5v5NzN/i87fIa0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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