SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5def82f414008dab37a18f1135c7e68a77995418f2b769d8a8ba45a1c5b968af' 
  AND token = '2sk1GFy9qtEFNdUkTmShPF9fveKyvqjd2wpU2Afpdpg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}