SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '451d721da00e8fe5d515dc113d83eecc372591a1eed4e027a459ce309c0fa599' 
  AND token = '5zbYDfEuGPD3vREELqC+ethh4AdiD5mvaRzHXxv/+sg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00048

JSON explain

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