SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '810df9599a64a41bf503a5021c32aedf384d6dc9e5cf77e99055fc5eecb978aa' 
  AND token = 'UwTR2OFVSQ5JDoFyfm/Bd6vMTadBE03Pu36OtpuEW+M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00048

JSON explain

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