SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '7630aa3e23af123645cff75751c2c433a26284a03a178a5570d9ae220e926a90' 
  AND token = 'YJG4tpHzVzOPsL+pViTpi/+zieqekEwwo+/FeyLpw8k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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