SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '8dc0890883521b595a6edc111402bd42e849062626e57362e71f0e63a5037c48' 
  AND token = 'tYVfjTnhil54/DYHHKrBY8sX0xcu6DG1jNrMtxIqPn4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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