SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '45221cf360e26408309a4537c846682ceade4ceb701a300f0e08b9264e2f6bef' 
  AND token = 'PZpu18aF+xXtvrvqRfh4yd3iBesrekbfV5TDM3RbzfM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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