SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '7caa8b129ff0a61d45ba2875c719e029ff90ab99ddbc81820017d3d222e4754f' 
  AND token = '+R1AbbB6sVP5ljBCt7tISGhpPBqyUupLyasLmLlo51c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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