SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1e85ecca1b2379ef1eb0a4cef82008602c23951e34382e32345dbe0e27fa2129' 
  AND token = 'toGrWq+f+JwL9vidGxXhbwL1DZpuxaOvLe4ajnsUeB4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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