SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '2a6e07b75668024e2a4741005d1b2af9a3509936d4e3809a73eb8784e2094fc9' 
  AND token = 'iT6VHjylIy0oku/VNxNDwAqAeP0M8EXPgxeCsjhKpG4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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