SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '978c36795a8ac94a4ac8a5bb15c61ccb5b2ce7b2e98315253885d6b2a436d707' 
  AND token = 'SxKFlPllh5SHeIHEy3fRepGFAERmhkg+cM8loVFfPqE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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