SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '36016935138b995539769c2c257f804d4b205103f036dad976ac5052bc8ad239' 
  AND token = 'qvKBLlG5FADhJ3uy+k7dNO43O9fhzprMwKcnLnDwJzc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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