SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '9c358ad12b189dd7bc4177ebadfb85cd854a20470457226c595828148d4d3298' 
  AND token = 'yd4rCjUzC+ONhoNf/HOYqpgTrz4E4MtHo0gAJCUwmUU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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