SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cd3a02e481f6bc3460fd168dd0be26e82084e442e43050a58e04b30c3684ba7f' 
  AND token = 'lmHSiCwLKLFQxCbBE92oEdpn9e4ph7kHhrqLyYdvjH0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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