Sandbox

SELECT 
  1 
FROM 
  lock_keys 
WHERE 
  key_id = 'cdca3954eec4a76b8d8025c405ce6d4bba43a1598dd117993ad9242a253775e5' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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