SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ae89fa441b22bdf534c6d2d3978128b99e75446feaae0f9619fe2e1715e9ac5f' 
  AND token = 'd9Q8lZgdFSBhhVUTmDhRC971NEKXLcMXWpeVa1GxQLk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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