SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '1c377331306d7c900c142e36c8948db10d7d64f051b81bb34521f513ad0975c3' 
  AND token = '5EaYomNh/q3zZqYFH0E2a6SR596voDlnMmHTCRhVf6M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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