SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'caa09d1ff2bfdbfc412e7dba8276d56fcb6d88a968632f0c478ea25f884047fc' 
  AND token = 'N5aN2CQkulLLMZ0bUAz7wnP9Bx3BTr3nEONCNjZVplo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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