SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3ad7b4a77163b997b78a468c6b52af8b32d7f884335c328484dfd6a231fb819b' 
  AND token = 'TvuI3urWqZ2DDWuMRZi8aPNRyOwkV4DR9I/in7sXWP4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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